Changes in Fair Value of Contingent Earn-Out Liabilities (Detail) (USD $) In Thousands	3 Months Ended	9 Months Ended
Jun. 30, 2011	Jun. 30, 2011
Fair Value, Measurement Inputs, Disclosure [Line Items]
Balance at beginning of period	$ 1,679	$ 724
Charges to acquisition-related costs, net	436	1,391
Balance as of June 30, 2011	$ 2,115	$ 2,115

This element represents total gains or losses for the period (realized and unrealized), arising from liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in earnings or resulted in a change in net asset value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 157
-Paragraph 32
-Subparagraph c(1)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration